Palm Pre won't stay locked

My Palm Pre will not stay locked, I can put it on standby or lock the screen (you know the button on the top left corner) and within a few seconds the screen will light up for like 7 seconds then turn off for 10 seconds and it will repeat this no matter what, and if I have it pugged into the charger it will just stay on. My Palm is setup to work with metro pcs so I don't want to doctor it and have to wait 3 days for this person to fix it for me so please help me out if you can guys!